DE3604396A1 - ELECTRIC POWER CONTROL SYSTEM FOR MOTOR VEHICLES - Google Patents

Description

description

The present invention relates generally to a power system for automobiles. In particular concerns The invention relates to an electrical power control system for automobiles that provides an auxiliary torque for control generated by a control servo using an electric motor.

With regard to problems of hydraulic power control systems, for example that their structure is complicated, recently became a multitude proposed by electrical power control systems for automobiles. For example, in Japanese Application Document No. 59-70257 describes an electrical power control system for automobiles.

This automotive electrical power control system includes an input shaft as a control shaft connected to the steering wheel, an output shaft, the via a universal joint with the input shaft and via a rack and pinion mechanism with a traction or Tie rod of a controlled wheel is connected, an electric motor that generates an auxiliary torque via an un-

OQ reduction gear applied to the output shaft, one Mechanism for determining the torque which is arranged on the input shaft and which is applied to the input shaft to determine the acting control torque, and a drive control circuit, which is based on a determination

gc lungssignales from the mechanism for determining the Torque a signal for the magnitude of the torque

and a signal for the direction of the torque that the Size and direction of the control torque that is applied the input shaft acts, each represent, can generate. This system uses the electric motor Armature current proportional to the signal for the size of the

Torque and in accordance with the line direction of the signal for the direction of the torque is supplied. The mechanism for determining the torque exists from a strain gauge sensor. 10

With such an arrangement, when the steering wheel is operated, an appropriate one is applied to the output shaft Auxiliary torque is applied from the electric motor, so that the control operation is facilitated.

In an electronic power control system according to however, the aforementioned Japanese Patent Laid-Open as in the case of an ordinary manual control system with no auxiliary power, a timing gear mechanism applied in which when a steering wheel in one direction, for example clockwise by a predetermined Angle is rotated from a neutral position, a rack on the output side is moved so that it is positioned at a corresponding end of its stroke ends, thus preventing the steering wheel from to be rotated further in the same direction. In general, the predetermined angle is about 540 ° or the same he about one and a half turns of the steering wheel.

In an electric power control system of this type according to the aforementioned Japanese Patent Laid-Open it is therefore desirable at the stroke ends of a rack on the output side, i.e. at both control ends of a steering wheel, reduce the auxiliary torque or stop generating it by an electric motor. This Desire arises from the fact that the lifespan of the

6 '■■; - · ■ -

electric motor itself as well as the whole power control system would thereby increase and that the consumption electrical power would be reduced, which would lead to power savings.

The present invention fulfills this desire in conventional ones Power control systems of the type described.

The object of the present invention is to provide ¹ Q a electric power control system for motor vehicles, in which under the condition that a steering wheel is rotated in the proximity of one of its control ends, the development of the auxiliary torque is at least reduced by an electric motor, whereby the The service life of the electric motor itself as well as of the entire power control system can be increased and, therefore, the consumption of electrical power is reduced, which results in power savings.

To solve this problem, the present invention provides an electric power control system for automobiles with an input shaft that is operatively connected to a steering wheel, an output shaft that is operatively connected to a steered wheel, an electric motor for effectively applying auxiliary torque to the Output shaft, a device for determining the control torque acting on the input shaft and a drive controller for applying a motor drive signal to the electric motor, taking into account an output signal from the device for determination the control torque. This system is improved by that a device for determining the steering angle of the controlled wheel and a correction device which makes an effective correction to the motor drive signal to reduce the amount of electrical Motor to be developed auxiliary torque below the

To reduce the condition that it is determined by the determining device for the steering angle that the steering angle of the steering wheel exceeds a predetermined angle.
5

The above features, other features, advantages, and aspects of the present invention still go more clearly from the following detailed description of a preferred embodiment of the invention emerged. This description is made in connection with the figures. It shows:

Fig. 1 is a longitudinal section through an electromagnetic servo device, which is an essential Part of an electrical power

control system for motor vehicles according to a preferred embodiment of the present invention Invention with a quarter cut away;

Fig. 2 shows a cross section along the line II-II

of Fig. 1;

3A shows a cross section along the line III-III of Fig. 1, which is a movable ferrous member

a sensor for the control torque in shows the electromagnetic servo device;

3B and 3C are a side view and a plan view of the

movable member of Figure 3A;

4 shows a cross section along the line IV-IV

of Fig. 1, which shows a sensor for the stouor rotation in the electromagnetic servo

device shows;

Figure 5 is a cross-section along the line V-V

of Fig. 1;

6 is a detailed block diagram of a control circuit of the electromagnetic

Servo device;

Fig. 7 is a further detailed block diagram of a circuit for determining the

IC control rotation in the control circuit of the

Fig. 6;

8 is a timing diagram of the output signals at various areas of the circle of FIG Fig. 7;

9A, 9B are schematic flow charts of main loop processes and interrupt processes executed in the microcomputer unit in the control circuit of FIG

will;

Fig. 10 is a diagram showing a relationship between

an integral value of output pulses representative of the control angle

of the rudder rotation detection circuit and a rudder angle;

Fig. 11 is a diagram showing a relationship between the integral value of for the control win

kel representative pulses and a correction value for a process in the unloaded Shows state;

Fig. 12 is a diagram showing a relationship between

a control angle signal and an armature

3 ~

current of an electric motor of the elec

Fig. 3 tromagnetic servo device;

Fig. 13 is a diagram for describing operational characteristics of the electric motor

the electromagnetic servo device, with relationships between the armature current, the number of revolutions and the load torque of the engine are shown; 10

14 is a diagram showing a relationship between the armature current of the electric motor and a drive current of a magnetic clutch of the electromagnetic servo device shows;

15 is a diagram showing a relationship between

a load torque applied to the electromagnetic servo device and one on the electromagnetic servo

device acting control torque shows; and

16 is a schematic block diagram of the Control circuit of FIG. 6.

40 ; ,

In Fig. 1, reference numeral 200 denotes the entirety of an electromagnetic servo device, which a essential part of an electrical power control system for motor vehicles according to a preferred embodiment of the present invention with which a vehicle, not shown, is equipped. The servo device 200 has an input shaft 4 which, with its right end according to FIG. 1, has a not shown Steering wheel of the control system is connected to a steering column 1, which receive the input shaft 4 inside can and is attached to an unillustrated body of the motor vehicle, an output shaft 7, the with its left end as shown in FIG. 1 with a control gear or control gear housing (not shown) for the controlled wheels (not shown) of the motor vehicle is connected and is arranged coaxially with respect to the input shaft 4, a housing 3 for receiving the output shaft 7 and a stator 2 of an electric motor 3 which will be explained later. The stator 2 is integrally connected to the column 1 and the housing 3.

The input shaft 4 is axially innermost loosely inserted into the axially innermost region of the output shaft 7, the innermost regions of the shafts 4, 7 are connected to one another via a torsion bar 8 which is arranged coaxially to the shafts 4, 7. the The input shaft 4 and the output shaft 7 are made rotatable in the correct position by a pair of bearings 9,10

ng or three bearings 11, 12, 13 stored.

The electromagnetic servo device 200 consists of a sensor 20 for the control rotation, which is arranged around the input shaft 4, a sensor 24 for the control torque around the loosely inserted innermost areas of the input shaft 4 and the output shaft

is arranged around, the electric motor 33, which is a DC motor which coaxially around the output shaft 7 is arranged around and can apply an auxiliary torque to the shaft 7, as will be explained later , a reduction gear 50, an electromagnetic clutch 63 and a control device in the form of a control circuit 75 for driving and controlling the electric motor 33 and the electric clutch 63 in accordance with corresponding detection signals received from the sensor 20 for the control rotation and the sensor 24 are sent out for the control torque.

More specifically, the input shaft 4 is divided into a first shaft 5 and a tubular second shaft 6. To the axially outer end of the first shaft 5, i.e. in Fig. 1 at the right end, the steering wheel is attached. With the axially inner end, the first shaft 5 is connected to the tubular second shaft via a rubber bushing 14, which is arranged in between to prevent the transmission of oscillations or vibrations. The rubber bushing 14 consists of a radial inner and a radial outer metal tube 14a, 14b and an elastic one Member 14c interposed therebetween. The inner tube 14 a is attached to the first shaft 5. The outer tube 14b is attached to the second shaft 6.

As shown in FIG. 2, there is also a fixed at the axially inner end region of the first shaft 5 annular part 15 placed, which has a pair of radially outwardly projecting projections 15 a, which in the circumferential direction are spaced from each other. These projections 15a are inserted into a pair of slots 6a, leaving a suitable angular gap. The slots 6a are at the axially outer end of the second Shaft 6, i.e. formed in Fig. 1 at the right end of this shaft. The first and second shaft 5, 6, the

it -.

are elastically connected to one another by the rubber bushing 14, can be angular relative to one another due to the gap be moved. In addition, they can by the annular part 14 with respect to each other and after a relative angular displacement can be locked between them, so that it is prevented that the elastic Part 14c is subjected to torques in its direction of rotation which are greater than predetermined torques. With the reference numeral 16 is a circular bracket denotes -IQ net, which prevents the annular part 15 from getting out of position.

As shown in FIGS. 3A to 3C, at the axially opposite end of the second shaft 6,

l§ ie, in FIG. 1 in the left end of the second shaft, a pair of axially extending grooves 17 are formed which are angularly spaced from one another by 180 °. In the axially innermost region of the output shaft 7, the diameter of which is enlarged and of which

2Q stator 2 held through a bearing 11a is a pair formed by projections 7a extending in the axial direction at positions corresponding to the grooves 17 of the second Corresponding to wave 6. The projections 7a are inserted into the grooves 17 with a predetermined gap in each case. In addition, the second shaft 6 is reduced in size at this same end, the smaller one Area is inserted into the enlarged innermost area of the output shaft 7 in order to be removed from the output shaft 7 to be held.

Furthermore, the second shaft 6 and the output shaft 7 are located in the corresponding axially inner end regions opposing axial holes formed coaxially with one another. The torsion bar 8 is in these holes arranged coaxially, with its one end (in Fig. 1 with the right end) by a pin 18 on the

second shaft 6 and with its axially opposite end through a further pin 19 to the output shaft 7 connected is. The axially outer end of the output shaft 7 is provided with serrations formed on it connected to the control gear or the control housing, which is a link on the load side, as described became. The torque applied by the steering wheel to the input shaft 4 is therefore deforming the torsion bar 8 is transmitted to the output shaft 7 and to the links on the load side. It should be noted that the rubber bushing 14, which is arranged between the first and the second shaft 5, 6 of the first shaft 4, stiffer or more rigid or is set to be harder with regard to its deformation than the torsion bar 8, which is between the second shaft 6 and the output shaft 7 is arranged.

As shown in Fig. 4, the control rotation sensor 20 includes a plurality of radially to outwardly protruding projections 21 in the form of equal angles from one another along the circumference of the second shaft 6 spaced teeth, and a pair of photocouplers 22a, 22b attached to the control post 1 in such a way that of each coupler the coupled parts are provided on both axial sides of the radial projections 21. By doing thus arranged sensor 20, the coupling by the light beam at each of the photocouplers 22a, 22b alternately interrupted by the projections 21 and the gaps 21a therebetween and produced when the Steering wheel is rotated when it is operated.

In this connection, it should be noted that the photocouplers 22a, 22b light-emitting elements 22c, 22e, composed of LED elements and light receiving elements 22d, 22f composed of phototransistors, as shown in FIG. The respective positions of the photo couplers 22a, 22b become

so determined that the periods of their detection of the projections 21 and the gaps 21a with respect to their phase from each other be shifted by a predetermined value, which in this embodiment corresponds to a quarter of each cycle.

More specifically, the circumferential widths of each of the protrusions become 21 and each of the columns 21a are set to be the same. Assuming this width is W, they are Positions of the photo couplers 22a, 22b in the circumferential direction spaced from each other by a distance (n + 1/4) .2W, where n, which is the unit in this embodiment represents an integer.

If the second shaft 6 is therefore rotated in one direction when the steering wheel is operated, the send Phototransistors 22d, 22f emit a pair of electrical signals that are 1/4 cycle out of phase with one another are.

The control torque sensor 24 comprises a differential transformer, which consists of a movable tubular ferrous core member 25 which is axially slidable around the mutually engaging innermost regions of the second shaft 6 of the input shaft 4 and the Output shaft 7 is placed around. In addition, the sensor 24 has a winding part 28. As shown in Fig.3A 1 to 3C, a pair of first elongated holes 25a extending through the movable core member 25, the engage a pair of pins 26 projecting radially from the axial projections 7a of the output shaft 7, and a pair of second elongated holes 25b which engage another pair of pins 27 that of the second Shaft protrude axially. Each of these radial pins 27 is from one of the radial pins 26 by an angle of 90 ° apart. The first elongated holes 25a are in

4S

the axial direction of the core member 25 is formed. The second elongated holes 25b are with respect to the axis of the member 25 inclined at a required angle. As a result, the inclined elongated holes 25 act in FIG Correspondence with an angular difference developed in the circumferential direction between the second shaft 6 and the output shaft 7 with the pins 26 engaging them to cause the movable core member 25 moves in the axial direction so that it is in agreement with the one on the input shaft 4 or on the second shaft 6 of the input shaft 4 acting control torque is shifted.

More specifically, in the case where, for example, it is assumed that the control torque is set to the second Shaft 6 clockwise viewed from the steering wheel side and a load torque greater than that Control torque are exerted on the output shaft 7, the second shaft 6 relative to the output shaft 7 clockwise rotated from the side of the steering wheel. Then the movable core member is caused to move upwards in Fig. 3C, i.e. to the right in Fig. 3B or to the left in Fig. 1.

In contrast, in the case where the second shaft 6 is counterclockwise relative to the output shaft 7 is rotated as viewed from the side of the steering wheel, causes the core member 25 to align with the above said direction moves in the opposite direction.

In any of the foregoing cases, the core member 25 is due to the inclined elongated holes 25b of the movable Core member 25 engaged by radial pins 26 provided on the output shaft 7 side are, the holes 26 are shaped so that they have a rectilinear shape when the tubular core

member 25 is manufactured or developed axially in the direction of movement from an original central position or neutral position in relation to the relative angular displacement in the circumferential direction between the second Shaft 6 shifted as a link of the input side and the output shaft 7.

In this connection, it should be noted that the movable core member 25 under the condition at the middle Position can be arranged that no control torque acts on the input shaft 4 and that therefore the relative angular displacement between the second shaft 6 and the output shaft 7 is kept at zero. In the in The state shown in FIGS. 1 and 3A to 3C is assumed, that the core member 25 is in this middle position.

In the differential transformer, the winding area 28 disposed around the movable core member, a primary winding 29 to which a pulse signal is applied and a pair of secondary windings 30, 31 arranged coaxially on both sides of the primary winding 29 and can generate an output signal corresponding to the axial displacement of the core member 25. if the relative angular displacement between the second Shaft 6 and the output shaft 7 developed in the event of a deformation of the torsion bar 8, is accordingly the axial displacement of the movable core member 25 converted into the electrical signals to be transmitted.

The electric motor 33 includes a stator 2 with a

cylindrical shape, which with the help of bolts 34 in one piece or integrally with both the control column 1 as also connected to the housing 3, the stator 2 having at least one pair of magnets 36 attached to its inside and a rotor 37 which is rotatably arranged around the output shaft 7. The rotor 37 includes a tubular shaft 38 which is freely rotatable on the output shaft 7 with the help of needle bearings 12, 13 is placed, which are arranged between them. In in a similar manner, the rotor 37 is supported by the housing 3 via a ball bearing 13a. Also includes the Rotor 37 is an armature unit which is mounted in one piece on the tubular shaft 38. This unit consists of a layered ferrous core 39, in which inclined slots for arranging a first multiple winding 40 and a second multiple winding 41 provided above are, with a fine air gap between the magnets 36 and the second winding 41 remains. aside from that A first commutator 42, which is connected to the first multiple winding 40, is on the tubular shaft 38 and a second commutator 43 connected to the second multiple winding 41 is attached. Also will a set of brushes 44 effectively brought into contact with the first commutator 42. Another set of brushes 46 is brought into contact with the second commutator 43 in a similar manner. The brushes 44, 46 are each in Brush holders 45, 47 which are attached to the stator 2 contain. The connecting wires of the brushes 44, 46 leave the stator 2 via non-magnetic tubes 2a, 2b. In the previous embodiment, the magnets 36 act the first multiple winding 40, the first commutator 42 and the brushes 44 together to form a direct current generator 48 as a sensor for the motor speed to form the number of revolutions per unit time of the rotor 37 of the electric motor 33 to be determined. This generator 48 can therefore be used to generate an output

AS

signal in the form of a DC voltage which is proportional to the number of revolutions of the rotor 37. On the other hand, the magnets 36, the second multiple winding 41, the second commutator 43 and the brushes 46 act

δ together to a suitable electrical range of the electric motor 33 for generating the auxiliary torque to build.

The reduction gear 50 comprises two stages 51, 52 of planetary gears which are arranged around the output shaft 7. As shown in Fig. 1, the first stage 51 consists of a first sun gear 38a, which runs along the outer periphery of the left end region the tubular shaft 38 is formed, the right half of a common slewing ring 53, which runs along the inner periphery of the housing 3 is formed, three first planetary gears 54, which between the sun gear 38 a and the turntable 53 are arranged and engage in this, and a first carrier part 55, which the planetary gears 54 rotatably holds. The carrier part 55 is placed loosely on the output shaft 7. The second stage 52 consists of a second sun gear 56a formed along the outer periphery of a tubular part 56 which connected in one piece or integrally to the first carrier part 55 is, the left half of the common slewing ring 53, three second planetary gears 57 between the Sun gear 56a and the ring gear 53 are arranged and engage in them, and a second carrier part 58, the the planetary gears 57 rotatably holds. On radially extending inner sides of the carrier part 58 is one piece integrally formed inner tubular portion 60 which is held by the output shaft 7 via a bearing 59. At the Extending in the radial direction outside of the carrier part 58, an outer tubular area 61 is integrally formed, which extends along the inner circumference of the housing 3. The outer tubular portion 61 has in-

teeth 61a formed along its Uitifang are. Therefore, when the rotor 37 of the electric motor 3 rotates, the rotation of the rotor 37 becomes via the tubular Shaft 38, the first sun gear 38a, the first planetary gears 54, the first carrier part 55, the second sun gear 56a and the second planetary gears 57 to the second carrier part 58 and therefore transferred to the outer tubular portion 61 thereof, the speed decreasing or is squat.

In the electromagnetic clutch 63, a rotor 64 of the same is rotatably supported by a bearing 66 on a ring part 65, which is attached to the output shaft 7 by serrations. The rotor 64 is for absorbing torsional vibrations elastically connected to the output shaft 7 via a ring-like elastic member 67. The tubular trained rotor 64 has an axial extension which extends as far or long as the inner surrounding tubular region 60 of the second support part. This extension has a pair of protrusions 64a extending radially inward from the inner periphery of the extension towards the outer periphery of the Output shaft 7 protrude. As shown in Fig. 5, the radial projections 64a are in a pair inserted from slots 65a formed in the ring member 65 with a required circumferential gap therebetween remains in each case so that the projections have an angular engagement relationship with the ring part 65. The rotor 64 can therefore, during a relative angular displacement between it and the output shaft 7, elastic with the output shaft 7 are kept connected, this displacement corresponding to the circumferential gap or before the projections 64a of the rotor 64 adjoin the ring part 65. The axial extension of the rotor 64 faces along its outer periphery External teeth 64b formed thereon. Also, the rotor 64 at the opposite end of the

axial extension of the rotor in relation to the second carrier part 58 at a position on the rotor a disk-like Carrier plate area 64c, which protrudes in the radial direction. Between the carrier plate area 64c δ of the rotor 64 and the second carrier part 58 a plurality of disk-like plates 68 are arranged alternately, in the outer peripheries of which grooves are cut which correspond to the inner teeth 61a of the outer tubular Comb area 61 of the carrier part 58. In addition, a plurality of disk-like plates 69 are provided, grooves are cut into the inner circumferences, which with the external teeth 64b of the axial extension of the Rotors 6 4 comb. This forms a multi-plate clutch mechanism. In Fig. 1, the reference numeral Chen 70 denotes a stop of the plates 69.

In addition, an annular opening 71 is provided and fixed therein at the axially outer end of the housing 3, the has a channel-like cross section. This annular opening 71 accommodates an annular excitation coil 72, which is connected to the control device 75 via a lead wire. In this way it becomes a power line built up by the excitation coil 72 a field of an electromagnetic force, through which a non As shown in the suitable device shown, the aforementioned plates 68, 69 are all drawn together against the spool 72 be, so that an auxiliary torque, which is from the electrical Motor 33 to the outer annular region 61 of the second carrier part 58 with respect to its speed the reduction gear 50 was transmitted in a stocky manner, normally further via the multi-plate having Coupling mechanism consisting of the elements 61a, 68, 69 and 64b, the rotor 64 and the elastic Member 67 is transmitted to the output shaft 7. In this context it is pointed out that in a state in which the rotor 64 rotates relative to the output shaft 7

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until the relative angular displacement between the Rotor and the output shaft reached a predetermined value, the radial projections 64a from the axial extension of the rotor 64 on corresponding side surfaces of the slots 65a adjoin the ring part 65, so that the auxiliary torque by the electric motor 3 3 mechanically is transmitted from the rotor 64 to the output shaft 7 in a non-elastic manner.

The control device 75 which functions as a control circuit for the electromagnetic servo device will now be explained 200 serves. The explanation takes place in connection with FIG. 6.

In Fig. 6, reference numeral 76 denotes a microcomputer unit. Corresponding detection signals S- to S ^ are applied to the microcomputer unit 76, which from a determination circuit 77 for the control torque, a steering rotation detection circuit 82, an engine speed detection circuit 120, and a Determination circuit 114 are sent out for an irregularity.

The determination circuit 77 comprises the aforementioned sensor 24 for the control torque, a drive unit 78, the a reference clock pulse T .. in the microcomputer unit while dividing it in a number of stages to which Primary winding 29 of the sensor 24 for the control torque sends out a pair of rectifiers 79a, 79b for rectification corresponding analog electrical signals generated by the secondary windings 30, 31 of the sensor 24 for the Torque in accordance with the axial displacement of the movable core member 25 of the sensor 24 is sent out become a pair of low-pass filters 80a, 80b for eliminating of high frequency components of these rectified signals and an analog / digital converter 81 for converting

corresponding analog electrical signals from the low-pass filters 80a, 80b into a pair of digital signals which are sent out to the microcomputer unit 76 _{as control torque signals S 1} , S _2.
5

The engine speed determination circuit 120 includes the aforementioned generator 48 as a sensor for the rotational speed of the motor and a low-pass filter 121 for eliminating high frequency components of an analog voltage signal sent from generator 48. An analog voltage signal sent out by the low-pass filter 121 is applied to the A / D converter 81, from which it is converted into a digital signal is converted, which is sent out as an armature speed signal so that the speed of rotation of the armature 37 represents the same corresponding to the number Nm of revolutions per minute. Like this later As will be explained, the engine speed determination circuit 120 may function as a feedback signal generator.

As shown in Figs. 6 and 7, the detection circuit 82 for the control rotation comprises a signal generator 83 which can apply an electric power to the photocouplers 22a, 22b of the sensor 20 for the control rotation so that the aforementioned electrical signals can be sent out, a wave shaping circuit 84, which consists of a pair of Schmidt trigger circuits 84a, 84b for appropriate or correct shaping of the waveform of the output signals from the signal generator 83, and a drive unit 85. This consists of a flip-flop quad or four flip-flops 87, 88, 89, 90 of the D-type, which can work with a clock pulse that is sent from a terminal CL _{2 of} the microcomputer unit 76, a multiplexer 91, which is a double four- Channel circle, and an exclusive OR circle 86.

In such a determination circuit 82 for the control rotation, in the case in which, for example, in a Rotation of the steering wheel clockwise, the projections 21 as light-shielding parts and the column 21a as interposed light-transmitting parts rotated clockwise from the side of the steering wheel become that the phototransistors 22d, 22f, which cooperate with each other with a phase difference, which corresponds to 1/4 cycle, receive these rays of light, which are emitted by the LED elements 22c, 22e and from time to time through a corresponding area of the light transmitting Areas 21a and the next following area are each transmitted. In this case, therefore, the aforementioned output from phototransistor 22f by 1/4 cycle in phase with that of the Phototransistor 22d delayed. As a result, the in output signals shown in FIG. A more detailed description will be given later.

Incidentally, the multiplexer 91 can operate in accordance with the truth table shown below.

Control connections 91b 91a Auscränae "S _n X X Fn H L. L. L. L. L. H DnO L. H L. DnI L. H H ^D n2 L. Dn3

In the above table, the reference character H denotes a high level "high". The reference character L denotes one low level 'low ". X can be either a high level H or a low level L. The suffix η is 1 or 5

In connection with FIGS. 7 and 8, numerous interrelationships among the output signals A. to A., B ₁ to B. and S ₁ to S _fi at essential areas of the determination circuit 82 for the control rotation will now be described.

As has been described, the clock pulse from the terminal CL- of the microcomputer unit 76 is applied in the determination circuit 82 to the drive unit 85. This signal is obtained by dividing the system clock T _{1 of} the unit 76 at a predetermined number of stages.

If the steering wheel is rotated clockwise, for example, as has been described, the aforementioned electrical signals, which are shifted from one another by 1/4 cycle, are applied by the signal generator 83 to the wave-shaping circuit 84, in which the Schmidt triggering circuits 84a, 84b Generate square pulse _{signals A 1} , B ₁ that are emitted. These signals also differ in phase by 1/4 cycle from each other. In the example shown in FIG. 8, the signal B ₁ , which is sent out by the circuit 84b, is delayed by 1/4 cycle with respect to the output signal A ₁ from the circuit 84a.

The output signals A ₁ , B ₁ are applied to the D connections of the flip-flops 87, 88, respectively. These are triggered in such a way that their output _{signals A 2} , B- are delayed with respect to the rising edge / falling edge of signals A ₁ , B _{1 by} a maximum of one period which corresponds to one cycle of the clock pulse from terminal CL _2.

In addition, the output signal A- of the flip-flop 87 is on

applied to the D terminal of the next flip-flop 89, which is triggered in such a way that its output signal A, at the Q terminal is delayed from the signal A "with regard to the rising edge / falling edge by a period that is a maximum of one cycle of the clock pulse from the terminal CL _{corresponds to 0. At the} same time, the flip-flop 89 sends an inverted signal A. to its Q terminal, the level of which is reversed with respect to the signal A.
Similarly, the output B "of flip-flop 88 is applied to the D terminal of the next flip-flop 90 which is triggered to change its output at the Q terminal with respect to the rising / falling edge of signal B" is delayed by a period which corresponds to one cycle of the clock pulse from the terminal CL "at the most. At the same time, the flip-flop 90 sends an inverted signal B ₄ at the Q terminal, the level of which is reversed with respect to the signal B ^. The input signals A- ,, A ₄ , B ", B. are then sent to the input connections D ₁₀ , D ₁₁ , D ₁₂ , D ₁₃ , D ₂₀ , D ₂₁ , D ₂₂ , D _{23 of} the multiplexer 91 via the lines shown in FIG 7 are applied. The two control connections S, S are grounded under the control connections 91a, 91b, UL, S _{7 of the multiplexer 91.}

At the output connections F ₁ , F ″ of the multiplexer 91, the logic of which is shown in the truth table above, signals S ₅ , S _{g appear} , the waveforms of which are shown in FIG. More precisely, the signal S ₁ - in FIG. 8 is held continuously at the "low" level, while the signal S _{1 has} four square-wave pulses during one cycle of the output signal A 1 or, more precisely, during one cycle of the output signal A ".

In addition, in the drive unit 85 of the determination circuit 82 for the control rotation, the output _{signals A 1} , A _{9 of} the wave shaping circuit 84 are applied to the exclusive OR circuit 86, which in turn _{emits the signal S 4} , which has two square-wave pulses that occur in one cycle of the signal A ₁ appear as shown in FIG.

It should be noted that the timing diagram of FIG. 8 corresponds to the case in which the steering wheel in FIG Way is rotated clockwise.

In contrast, in the case where the control wheel is rotated counterclockwise, the corresponding pulses in the signal A .. are _{delayed from corresponding pulses in the signal B 1} by 1/4 cycle and become different signals A depending thereon ₂ to A ₄ , B ₂ to B, and S ₄ to S _fi generated and transmitted. In this case, therefore, the waveforms of the signals Sc, Sg, as shown in FIG. 8, are interchanged with one another, while the waveform of the signal S ₄ is retained.

It is easy to understand that the duration of those pulses which appear in the signals A ₁ , B ₁ as the quasi-original detection signals is inversely proportional to a steering speed Ns of the steering wheel.

As can be seen from the above description, appear among the output _{signals S 5} and Sg of the determination circuit 82 for the steering rotation only in the signal Sg pulses when the steering wheel is rotated clockwise, and only in the signal S ^ pulses when the steering wheel is turned in the opposite direction is turned clockwise.

The output _{signals S 4} to Sg of the detection circuit 82 for the control rotation are applied to the microcomputer unit 76 and in particular to three counters (not shown) in the microcomputer unit, while the clock signal, which is represented by the terminal CL ₂ , is sent to a further counter (not shown) in FIG Unit 76 is applied. In the microcomputer unit 76, the input signal S ₄ from the detection circuit 82 is used as a signal for calculating the control speed Ns. In addition, the input signals S ₅ and Sg from the determination circuit 82 are used in the unit 76 as signals for calculating the steering angle Th of the steering wheel.

The microcomputer unit 76 necessarily includes not shown I / O or input / output units, a Memory, processor and controller.

To control the microcomputer unit 76 as well as other circuits, an electrical power circuit 92 is provided, which comprises a normally closed relay 96 which is arranged in a power line which is fed from a positive terminal of a battery 93 mounted in the vehicle via a key switch 94 of an ignition switch IG. SW. And a fuse is derived, and a voltage stabilizer 97, to which the electrical power is applied via the relay 96, has. The relay 96 has an output terminal 96a for applying electric power from the battery 93 to a drive circuit 100 for the electric motor and a drive circuit 108 for the electromagnetic clutch. The voltage stabilizer 97 has an output terminal 97a for applying the stabilized power or voltage to the micro-computer unit 76 and other circuit elements. While the key switch 94 is switched on, the microcomputer unit 76 is therefore brought into an excited state in which it can process the corresponding input signals S- to S ^, following a program stored in the memory in order to generate three control signals T ₃ , T ₄ , Tr, which are used to control the electric motor 33, and to _{send out a control signal T g} for the current of the clutch, which is used to control the electromagnetic clutch 63, the control circuit 100 of the motor and the control circuit 108 of the clutch, in order to thereby achieve the Control of the motor 33 and the clutch 63 to control. Among these control signals, T ₃ and T _{4 represent} clockwise rotation and counterclockwise rotation signals which are responsible for determining the terminal polarity of an armature voltage Va applied to the electric motor 33 in accordance with the

ig : ■ - ■■ '■ "■■■■

The steering direction of the steering wheel are to be applied. T ₅ is a voltage control signal which is responsible for determining the armature voltage Va.

The drive control circuit 100 for the electric motor comprises a drive unit 101 and one of a pair of relays 102, 103 and a pair of npn transistors 104, 105 existing bridge circuit. In the bridge circuit, the relays 102, 103 have a common supply connection, which is connected to the output terminal 96a of the relay 96 of the power circuit 92. Also are the emitter connections of the transistors 104, 105 are commonly connected to ground via a resistor 106. Against this are the corresponding Excitation coils of the relays 102, 103 and the base connections of the transistors 104, 105 each with output connections 101b, 101a and 101c, 101d of the drive circuit 101 are connected. The collector connections of the transistors 104, 105 work together to generate a potential difference which is used as the armature voltage Va across the aforementioned brushes 46, 46 to the second multiple winding 41, which is an armature winding of the electric motor 33 represents, is applied.

The drive unit 101 of the drive circuit 100 of the motor can drive the relay 102 or 103 and the transistor 105 or 104 in accordance with the control signals T ₃ , T ₄ , which are representative of the direction of rotation, and a pulse signal as a series of PWM waves (Pulse duration modulation) to the base of the transistors 104, 105, which by modulating the duration of a square-wave pulse signal of a constant frequency in accordance with the voltage control signal T ₁ . is obtained.

In a state in which the determination signals S ₁ , S ₂ representing the control torque are made so that they represent a control torque of a certain size

13 -> * - 360Λ396

acting clockwise on the input shaft 4, the microcomputer unit 76 sends in a manner to be described later the signals T ₃ , T representative of the clockwise and counterclockwise rotation in the form of a high level "high" and one, respectively low level "low" and the voltage control signal T ₅ with a signal value which corresponds to the above control torque. Then, the drive unit 101 is caused to energize the relay 102 through the terminal 101b and at the same time apply the aforementioned pulse signal, the pulse width of which is _{modulated in accordance with the value of the voltage control signal T 5} , to the base terminal of the transistor 105 through the terminal 101d. Under these circumstances, the effective value of the armature voltage Va to be applied to the electric motor 33 is proportional to the duration of the modulated pulse signal. The armature voltage has a terminal polarity which is such that an armature current Ia flows in a conduction direction A, which causes the motor 33 to rotate clockwise.

In the above case, the drive unit 101 does not send an exciting current through the terminal 101a and does not send a pulse signal via the terminal 101c, so that the relay 103 remains de-energized and the transistor 104 is switched off remains or blocks.

In contrast, in a state where the control torque of a certain amount acts on the input shaft 4 in the counterclockwise direction, and therefore the microcomputer unit 76 sends out the signals T ₃ , T ₄ representative of the clockwise rotation and the counterclockwise rotation so that they have a page "low" or "high", and in which the voltage signal is transmitted with the signal value which corresponds to the control torque, a series of steps reversed in the direction is carried out. This causes

the relay 103 is energized and at the same time the transistor is turned on, so that the armature current Ia through the electric motor 33 runs in a direction of rotation B, whereby it is forced that the motor 33 against the Rotates clockwise.

In other words, in the drive circuit 100 for the electric motor is a process of controlling the direction of rotation of the electric motor 33 by a selective Power conduction to a combination of relay 102 and transistor 105 or an opposite combination of the relay 103 and transistor 104 as well as a process for effecting control of the conduction period of transistors 104,105 modulating duration of the pulses to be applied to the base terminals of transistors 104, 105, while the electric motor 33 is applied with the armature voltage Va having an effective value that is the Control of the line period corresponds. Thereby, the motor 33 is controlled so that it is an auxiliary torque in

2Q Correspondence with the steering torque applied to the steering wheel generated.

The drive circuit 108 for the electromagnetic clutch has a drive unit 109 and an npn transistor 110 on. The collector of 110 is connected to the aforementioned via the exciting coil of the electromagnetic clutch 63 Output terminal 96a of relay 96 connected in the power circuit. The emitter terminal of transistor 101 is via a resistor 111 with ground as a common connection

oQ Finally connected. The base of transistor 110 is connected to an output terminal of the drive unit 109. The drive unit 109 can be connected to the base connector of the transistor 110 apply a pulse signal, the duration of which in accordance with the control signal Tg for the clutch current which is sent out from the microcomputer unit 76. In the drive circuit 108 for the

Coupling, a process is therefore carried out on the drive unit 109 by which the control of the power line of the Transistor 110 in accordance with the control signal Tg is effected to thereby reduce the torque transmission of the electromagnetic clutch 63 to control.

As has been described, in the present embodiment of the invention, an anomaly detection circuit 114 that can detect anomaly of the electric motor 33 and the electromagnetic clutch 63 is employed. The determination circuit 114 has an amplifier 115a for amplifying a voltage signal which is applied to one connection of the aforesaid resistor 106 in the control circuit 100 for the motor, a further amplifier 115b for amplifying a voltage signal which is supplied by a connection of the aforesaid resistor 111 in the drive circuit 108 is removed for the coupling, a pair of low-pass filters 116a, 116b for removing high-frequency components of the output signals from the amplifiers 115a and 115b, respectively, and an analog / digital converter 117 for converting the analog signals sent out by the low-pass filters 116a and 116b, respectively digital detection signal which is applied as the aforementioned signal S ₇ to the microcomputer unit 76. In this connection it is pointed out that this determination circuit 114 can determine irregularities in the electric motor 33 and the electromagnetic clutch 63 by checking the corresponding connection voltages of the resistors 106, 111. In the event that an abnormality is detected by the circuit 114, the microcomputer unit 76 enters an abnormality diagnosing process by operating to apply a relay control _{signal T 2} to the relay 96 of the power circuit 92 to thereby power supply to interrupt for the circular elements.

Ira following are now various programmed functions of the microcomputer unit 76 is explained.

Figs. 9A and 9B show flow charts schematically Main loop processes and interruption processes in the Microcomputer unit 76 show. In these figures, 300 to 334 and 350 to 358 are assigned with the reference numerals Process stages or steps referred to.

By turning on the ignition key at the key switch 94 on the power circuit 92, the microcomputer 76 is like an electrical power is also applied to the other associated circuits. It is also made possible that this Execute control functions.

First, the control sequence goes to the initialization stage 30 2, where first and foremost various parameters and factors as well as circles in the Microcomputer unit 76 are initialized. At this moment the counters to which the output signal S, from the control rotation determination circuit 82 and the clock signal CL- are to be applied in each case, reset. In addition, a later-explained flag Fth, that is, the admissibility of the control in the unloaded or unloaded state concerns, set to "0". After that, an interrupt is switched on.

In this context, the electromagnetic servo device 200 a neutral position sensor for applying an interrupt request to the Microcomputer unit 76 when the neutral position of the input shaft 4 is determined by this.

The flow chart of Fig. 9B shows a one as a whole routine handling such interruption.

Immediately after the sequence to interrupt level 350 arrives, the interruption is deactivated in step 352. After that, i.e. after the neutral position of the Input shaft 4 has been detected once under the condition that the ignition switch IG.SW. is turned on hence the interrupt request from the aforementioned neutral position sensor to the microcomputer unit 76 not acknowledged by this.

In a subsequent stage or a subsequent step 354, both counters, to which the output signals S ₅ , S ₆ are to be fed from the determination circuit 82 for the control rotation, are each reset.

Furthermore, in the stage or in step 356, the content of a register Y, which will be explained in more detail later, is used for the Control angle cleared to zero.

Thereafter, in step 357, the flag Fth for permitting the control in the unloaded state is set to "1" set.

After completing all the necessary processes or steps through the aforementioned stages 352 to 357, the sequence is reversed in relation to the address at which the interruption request in question was raised , the next address back to a main loop shown in Fig. 9A.

It can be seen that in the present embodiment of the invention, the routine of Fig. 9B is used for processing the interrupt is programmed to provide a sequence of steps to determine the neutral position of the input shaft 4 and taking into account the control angle Th for the correct setting of a license plate, for resetting of the counter and to clear a register to zero.

In this context, however, a modified example can advantageously be used in which instead of the Execution of the above-described processing of the interruption the neutral position of an input shaft in a Microcomputer unit at the time of manufacturing the control system is stored and regardless of whether an ignition switch is on or off, the electrical Power is normally applied to a circle element that can save changes to the rudder angle.

In the main loop of FIG. 9A, in step 304, the detection signals S to S _{7 are} input from the corresponding detection circuits 77, 82, 114, 120 for reading and storing.

At the next step 306, as a step of a subroutine, failure diagnosis is carried out as to whether or not the detection signals S. to S_ are correct. The check is carried out in that the signals S .. to S ₇ are checked for irregularities. If any irregularity is found, the relay control signal T ~ is applied from the microcomputer unit 76 to the relay 96. This cuts off the power supply from the power circuit 92 so that the power supporting function of the electric power control system is stopped, thereby enabling the control system to be operated by human force.

More specifically, the control circuit 75 then terminates the control of the electric motor 33. In cases where below such a condition as to cause the input shaft 4 to be applied to the steering wheel Control torque is rotated in one direction, initially the torque transmission from the input shaft 4 to the output shaft 7 is effected via the torsion bar 8,

this leads to an increasing torsional deformation the same. And when a load torque so larger than that is applied to the output shaft 7 Control torque, so that it is caused that the relative angular displacement between the input shaft 4 and the Output shaft 7 develops so far that it reaches a predetermined maximum value are at that time the above-mentioned projections 7a of the axially innermost portion of the output shaft 7 for abutment against the corresponding ones Brought side walls of the grooves 17, which are arranged at the inner end of the second shaft 6 of the input shaft 4 are. An engagement relationship is established there, in which the output shaft 7 is mechanically and integrally with the input shaft 4 in the corresponding is rotated in one direction. Such an engagement relationship between the projections 7a and the output shaft 7 and the grooves 17 of the second shaft 6 of the input shaft 4 provides a safety function for the electromagnetic servo device 200.

In the case in which the detection signals S- to S ^ are all normal and correct, then in the subsequent step 308, which is a decision step, a comparison of the signal value between the detection signals S .., S ₂ from the detection circuit 77 for the Control torques representative of the control torque are carried out to thereby judge whether the control direction of the control torque is clockwise or counterclockwise. A decision is then made as to which of the signals Tj, T ^, which are representative of the clockwise rotation or the counterclockwise rotation, is to be set to the "high" level.

More specifically, it is judged at step 308 whether the signal value of the signal S "for the control torque im Clockwise is greater than the signal S "for the control

torque counterclockwise or not. Then when the In the event that the process goes to step 310 should, made a decision according to which the signal T ^ for the clockwise rotation is set to the "high" level and that for another assessment to the Step 312 is gone by the signal T. for the Counterclockwise rotation is set to the "high" level.

After these processes have been carried out, step 314 is proceeded to, in which an operation is carried out to determine the quantity D as the absolute value of the control torque from the signals S ₁ , S ₂ representative of the control torque such that D = / S-. - S ₂ / applies.

Subsequent to the process in step 314 is a process for controlling the unloaded state by a Group of steps 315-318 performed.

2C More specifically, at step 315 which is a decision step, it is judged whether the flag Fth for the Permissibility of the control in the unloading state is set to "1" or not. If the Fth indicator is not set to "1" is set, the flow advances to step 320, where the process for control in the unloading state is disabled or prevented, as will be explained later.

In the case where the flag Fth is set to "1", the flow advances to the next step 316 at which the content of the register Y (built-in) for the control angle is updated, following an arithmetic expression such that Y is = Y + (S ₅ ¹ + S ₅ ¹ ) applies. In this case, S ₅ ¹ , Sg ¹ are count values of the aforementioned counters for the determination signals S ₅ , Sg applied to them, which represent the control angle. These values are therefore always positive. When the steering wheel is out of his

neutral position is rotated clockwise Y therefore has a negative value and when the steering wheel is turned counterclockwise from its neutral position the value Y is positive.

In this connection, in step 304, count values of the signals S- to S- and of the clock signal CL "are read out in order to be stored. In addition, the counters of the signals CL ₂ , S., Sj-, Sg are cleared to zero immediately after their count values have been read out.

Between the absolute value I Y j of the content of the Register Y for the control angle and the control angle Th has a relationship that is shown in FIG. 10 by the straight lines Lines P is shown. In Fig. 10, the reference symbol Thmax denotes the maximum value which the steering angle Th of the steering wheel may have when the steering wheel is clockwise or counterclockwise is rotated. Th- denotes a predetermined value of the rudder angle Th, which is smaller than the maximum rudder angle Thmax, but is close to it. The absolute value amount I Y ί of the register Y becomes equal to the predetermined one Value Th- and the maximum value Thmax when the control angle Th is developed up to the values Th- and Thmax, respectively.

At step 317 which is a decision step following step 316, it is judged whether the absolute Value amount | Y i is smaller than the predetermined value Th.j or not. In the case where the amount I Y | smaller is Th-, the control angle Th is naturally smaller than the predetermined value Th-. The process therefore continues to the next step 320.

In contrast, when it is judged at step 317 that the amount | Yf is greater than Th-. At step 318 a correction

² '■■ ■■' ■ "''

value X subtracted from the size D of the determined control torque. In this respect there is between the absolute Value amount | Y j of the register Y and the correction value X of the size D have a relationship as shown in FIG is. However, when the value of the quantity D corrected in this way becomes negative, the quantity D is set to zero. In addition, even in the case where the absolute value | YJ becomes substantially equal to the maximum Control angle Thmax, the variable D is set to zero regardless of the IC correction value X.

In step 320, operations for determining the control speed Ns from corresponding count values of the clock signal CL ₂ and the output signal S, representative of the control speed, of the determination circuit 82 for the control rotation are carried out. Thereafter, operations are carried out in which, by a memory address designation based on the control speed Ns and the torque amount D, the voltage control signal T _{5 is given} a value which is used to determine the armature voltage Va, as will be explained later.

The count values of the clock signal CL "and the detection signal S ^ can preferably be read at step 320.

The following describes how the signal value of the voltage control signal Tr is determined.

As can be easily understood, between the input shaft 4 and the electric motor 33, which is via the reduction gear 50 and the electromagnetic clutch 63 is connected to the output shaft 7, which turns naturally essentially at the same rotational speed or angular speed as the input shaft 4

must rotate, there is such a relationship that N KN holds. Nm denotes. the rotational speed in the form of the number of revolutions per time which the motor 33 must execute when the input shaft is rotated _{at a control speed Ns 1.} K denotes the gear ratio of the reduction gear 50, which is given in the form of the ratio of the speed of the drive side to the speed of the driven side. In this connection, it should be noted that the electromagnetic clutch 63 can basically be operated so that the torque from the reduction gear 50 is transmitted as it is to the output shaft 7, while the exciting current Ic is transmitted to the clutch 6 3 in a manner described later is controlled.

The necessary speed Nm of the electric motor 3 3 is thus determined by the control speed Ns.

In the microcomputer unit 76, a set of numerical data of the Armature current Ia permanently or continuously addressed as a function Ia (D) of the variable D of the control torque, where the current Ia to the quantity D has the relationship shown in FIG. Therefore, if a value of size D of the control torque is specified, the value

the required armature current Ia (D) can be determined in the form of data from the stored data, the data can be identified by simply designating a corresponding address. It doesn't have to be special 3Q calculations are performed.

In addition, Fig. 13 shows the operational characteristics of the DC motor 33 shows that it is proportional to the increase in the load torque Tm on the motor the armature current Ia increases and the speed Nm of the motor decreases, while the armature to be applied to the motor

HO

voltage Va is kept constant. On the other hand, in the case where the load torque Tm is constant, the Speed Nm of the motor increases when the armature voltage Va increases while the armature current Ia is kept constant.

At this point in the description it will be noted that the required speed Nm of the motor is derived from the control speed Ns is determined and that the required armature current Ia (D) by address determination according to the IC size D of the control torque is determined.

In the memory of the microcomputer unit 76, in another area, is a set of numerical data of the armature voltage Va as a function of both the speed Nm of the motor and the armature current Ia, according to the one between them existing relationships, which are shown in FIG. 9, matrix-like uninterrupted bsw. stored permanently addressed. When specifying corresponding values for the speed Nm of the motor and the armature current Ia, the value

2C, the required armature voltage Va can be determined in the form of data from the stored data, which data can be identified simply by designating a pair of corresponding addresses. For example, in the case where the required speed Nm of the motor is determined to be N. in FIG. 13 and the magnitude of the control torque in FIG. 12 is given as a value D ₁ and the required armature current Ia (D) is thus determined so that the one shown in Figs. 12, 13 Ia. 13, a value V _{2 is} determined as the required armature voltage Va.

In accordance with such a certain value of the required armature voltage Va, the voltage control signal Tr is determined.
35

In practice, however, numerical data is the armature voltage

-Jt

Va stored so that the voltage Va by addressing can be determined in accordance with corresponding values of the speed Ns and the armature current Ia (D) can without the need to determine the required speed Hm of the engine from the control speed Ns is. The reason why such an operation is possible is because of the proportional relationship or linearity between the speed Nm of the motor and the control speed Ns.

The armature voltage Va is therefore determined by an address designation based on the signals S-, S ₂ representative of the control torque and the signal S ^ which designates the control speed. This leads to an increased control speed of the microcomputer system 76.

In the flowchart of FIG. 9A, in step 322, the control signal T ^ for the current of the electromagnetic clutch 63 is determined in accordance with the quantity D of the control torque. In connection with the signal T _fi , the determination is also made by address designation. More specifically, the excitation current Ic for the clutch is first determined by address designation according to the required armature current Ia

(D) determined from the calculated variable D of the control torque is determined. In this regard, the clutch current Ic to armature current Ia (D) has one in the 14 relationship shown. Then, in accordance with the clutch current Ic thus determined, the control signal becomes Tg determined for the clutch current. In Fig. 14 the reference symbol Ico denotes a bias component or a bias current component of the clutch current Ic, which is applied for the necessary absorption of, for example, frictional forces.

Then at step 324 with respect to the control speed

speed Ns determined by the signal S ₄ from the determination circuit 82 for the control speed and in relation to an apparent speed Nm ^{1 of} the engine represented by the signal S ₃ relating to the speed of the engine and from the determination circuit 120 for the number of revolutions of the engine is obtained, an intervening deviation M is obtained such that M = | Nm'-Ns] [. In other words, the deviation M is determined as an absolute value of the difference between the speed Nm ¹ and the control speed Ns, whereas this deviation is e.g. determined differently in the form of a ratio between the control speed Ns and the product of the speed Nm of the engine and the gear ratio K of the reduction gear 50 can be shown. The generator 48 of the detection circuit 120 may have an output characteristic that can ensure a relationship such that Nm ¹ = Nm / K holds. Nm ¹ denotes the apparent speed of the engine. Nm denotes the actual speed of the motor. K denotes the aforementioned gear ratio. The apparent speed Nm ^{1 of} the motor is therefore inherently directly comparable with the control speed Ns.

Then, at step 326 which is a decision step, judgment is made as to the size of the deviation M by judging whether M> M _n . M _Q denotes a predetermined critical value. If it is found that the deviation M is in an allowable range below the value M n, the flow goes to step 334, which is an out step in which the control signals T 1, T 1, T 1, T _fi are sent out as they are determined until then without the signal T _n . to control the armature voltage and the signal T ₆ to control the clutch current are corrected.

In the case where the deviation M is larger than that

HS

Value M is proceeded to the next step 3 28 which is a decision step in which the apparent speed Nm ^{1 of} the engine and the control speed Ns are compared with each other by judging

whether Ns => Nm 'applies. >

Then, in the case where the control speed Ns is faster than the speed Nm 'of the motor, step 330 is proceeded to, where an increase correction of the control signal IV for the voltage is carried out to increase the armature voltage Va by thereby increasing the actual number of revolutions Nm in the form of the number of revolutions of the electric motor 33. In accordance with this, an enlargement correction of the signal T _ß for controlling the clutch current is carried out.

In contrast, if the control speed Ns is less than the apparent speed Nm ^{1 of} the motor, step 332 is proceeded to, in which a reduction correction of the signal Tr for controlling the voltage is carried out to thereby determine the actual speed Nm of the motor and also of the signal To make Tg to control the clutch current smaller. The process then proceeds to output step 334.

By correcting the control signals T ₅ , T _g in steps 324, 326, 328, 330 and 332, very small changes in the operation of the electric motor and fluctuations in the feeling of control, which result in very small changes in the operation of the friction elements of the electromagnetic clutch 63 and the reduction gear 50 are eliminated.

At output step 334, the control signals T ₃ , T. for the direction of rotation of the motor and the signal T ₅ for

HH .. .- ■

Control of the armature voltage, if necessary, in the corrected form, to the drive circuit 100 for the electrical Motor sent out. In addition, the signal T ^ is used for control of the clutch flow, if necessary in the corrected Form, sent to the drive circuit 108 for the electromagnetic clutch.

As has been described, in the drive circuit 100 for the motor, PWM control of the armature voltage Va of the electric motor 33 is carried out in accordance with the signals T-, T * controlling the direction of rotation and the voltage control signal Tr. At the same time, the excitation current Ic for the electromagnetic clutch 63 is controlled in the drive circuit 10 8 for the clutch as a function of the signal T _ß for controlling the clutch current by pulse width modulation, so that the clutch force of the clutch 63 is proportional to the armature current Ia or output torque Tm of the electric motor 33 controlled throw. This effectively prevents useless or particular consumption of electrical power at the clutch 63.

Finally, a return is made to step 304.

The diagram in FIG. 15 shows the manual or powerless operation and the power-assisted operation relationships between the control torque Ts acting on the input shaft 4 and the load torque, respectively Tl, which is exerted on the output shaft by the control gear. With the small letter _1 there is a straight-line characteristic curve referred to in the powerless operation of the control system, for example followed in the case where the operation of the control system in step 306 is ended. The big letter L denotes a characteristic curve peculiar to the power-assisted operation of the control system or is relevant.

From Fig. 15 it can be seen that according to this embodiment, in which the size of the armature current Ia from the size D of the control torque using a Relationship between these, which is provided as in FIG. 12, is determined, the power-assisted Characteristic essentially the powerless characteristic in a range of a small load torque Tl overlaps. In other areas in which the load torque Tl is still increased beyond that, the power assisted operation characteristic curve L is successfully kept substantially flat. If the load torque Tl is increased further along a range Re, which is such values of the load torque covered, which correspond to those values of the control angle Th that are found in an area are ranging from the predetermined value Th ^ to reaches the maximum value Thmax, the power-assisted characteristic curve L gradually rises and coincides finally with curve _1 for the powerless characteristic. The reason why the performance-based Characteristic is variable as shown by curve L of Fig. 15 is based on the one hand that the armature current Ia is determined relative to the size D of the control torque, such as this is shown in FIG. On the other hand, this reason is based on the fact that the size D of the control torque in advance in steps 315 to 318 in the manner described, taking into account the control angle Ls Th is corrected, which has the consequence that the armature current Ia is changed relative to the load torque Tl, as shown in Fig. 15 by the broken line. In this context it arises from Fig. 14 that the clutch excitation current Ic is changed proportionally to the armature current Ia.

In view of the foregoing, it is advisable that

the load torque Tl during the journey of the vehicle practically in a fixed or substantial ratio to Steering angle Th is.

Fig. 16 shows a schematic block diagram in which various functions of the control circuit 75 thereby are described that interrelationships between between essential elements of the circle 75 shown in FIG. 6 and associated process steps in 9 with regard to the Pro-XO Zeß for the control in the unloading state ■ shown are. In this way, the circles, detection signals, Process steps and control signals are eliminated that have no direct relationship to the process of control in the Have a state of relief.

According to the preferred embodiment of the present invention, the armature voltage Va of the electric motor 33 is basically determined as a function of the signals S ₁ , S "for the control torque and the signal S for the control speed, so that the actual rotational speed Nm of the motor 33 is advantageous is adapted to the control speed Ns of the input shaft 4 and therefore also of the steering wheel. This ensures an optimal feeling of control.

In addition, as a specific point in steps 315 to 318, a process for control in the unloading state is carried out which enables, when the steering wheel approaches one of the two control ends " ₀ ", the armature voltage Va applied to the electric motor 33 to be gradually increased is reduced and finally becomes zero at the end of control, so that the auxiliary torque developed on motor 33 is also correspondingly reduced and finally becomes zero at the end of control.

As a result, the life of the electric mo-

Η}

gate 33 itself as well as that of the entire power control system is effectively enlarged. At the same time, the Consumption of electrical power of the entire system and in particular of the motor 3 3 reduced, so that power can be saved. In addition, the unloaded control process continues to contribute Improve the feeling of being in control.

In the above embodiment, until the control angle Th when it exceeds the predetermined value Th- has reached the maximum control angle Thmax, the size D of the control torque, which is based on data of the Control angle is based, gradually and continuously decreasing corrected until it is finally reduced to zero. It should be noted that the size of the Torque, which is based on such data, advantageously can be reduced so that it can be intentionally reduced by a straight line or stepwise reduction or in extreme Cases even with no reduction on the way to one. Zero state can be corrected at the control end should be achieved.

It should be noted that the present invention relates to an electric power control system, in an auxiliary torque developed on an electric motor is made small or zero when a steering wheel is in the vicinity of one of its two steering ends is rotated. The present invention is therefore effectively applicable in connection with any power control system, which has an electric motor which is suitable for developing an auxiliary torque.

It should be noted that the mechanisms required to determine the end of control are arbitrary can be made. For example, a code wheel on a control shaft for displaying a

Control angle range near the control end can be used. In addition, a limit switch can be used to determine the control end is advantageously provided on a control shaft or in a rack and pinion mechanism itself will.

Claims (8)

Mentor lawyers Dipl.-Ing. H. Weickmanij, Dipl.-Phys. Dr. K. Fincke Dipl.-Ing. R A.Weickmahn, D-.pl.-Ciiem. ß. Huber Dr.-Ing. H. LiSKA, Dipl.-Phys. Dr. J. Prechtel <l «Γ · - ■ - ■ {■ (· £ ■ 8000 MÜNCHEN 86 XL · i!; Ί: = ί · ίθϋ POST BOX 860 820 MOHLSTRASSE 22 TELEFON (0 89) 9S 03 52 TELEX 5 22 621 TELEGRAM PATHNTYF.ICKMANN .MUNICH VP / He HONDA GIKEN KOGYO KABUSHIKI KAISHA 1-1, Minami-Aoyama 2-chome, Minato-ku, Tokyo 1o7, Japan Electrical power control system for motor vehicles Patent claims An electric power control system (200) for automobiles comprising an input shaft (4) operatively connected to a steering wheel, an output shaft (7) operatively connected to a controlled wheel, an electric motor (33) operatively connected to an auxiliary torque applied to the output shaft (7), a device (77) for determining the control torque (Ts) acting on the input shaft (4) and a drive control device (76, 100, 108) for applying a drive signal (Va) to the electric motor (33 ) taking into account an output signal (S., S ₂ ) from the determining device (77) for the control torque, characterized in that a device device (82, 315, 316) for determining a steering angle (Th) of the steering wheel and a correction device (317, 318) are provided which carries out a correction to the motor drive signal (Va) under the condition that the determined by the determination device ( 82, 315, 316) for the control angle determined control angle (Th) of the steering wheel _{exceeds a predetermined angle (Th 1} ), to decrease in order to thereby reduce the auxiliary torque to be developed on the electric motor (33). 2. System according to claim 1, characterized in that the correction device (317, 318) can correct the motor drive signal (Va) decreasing to zero when the control angle (Th _{) has exceeded the predetermined angle (Th 1} ), thereby the operation of the to finish electric motor (33). 3. System according to claim 1 or 2, characterized in that the predetermined angle is close to a maximum steering angle (Thmax) of the steering wheel. 4. System according to claim 3, characterized in that the correction device (317, 318) can carry out an effective correction in order to reduce the motor drive signal (Va) and finally to reduce it to zero when the control angle (Th) from the predetermined angle (Th ₁ ) is changed to the maximum control angle (Thmax), thereby reducing the auxiliary torque to be developed on the electric motor (33) and finally ending the operation of the electric motor (33). 5. System according to claim 4, characterized in that g e k e η η - indicates that the correcting means (317, 318) effectively and uninterrupted the motor drive signal (Va) can correct down to zero. 6. System according to any one of claims 1 to 5, characterized in that the motor drive signal (Va) / which is to be applied by the drive control device (76, 100, 108) to the electric motor (33), an armature voltage signal (Va). 7. System according to one of claims 1 to 6, characterized in that an electromagnetic Coupling device (63) for the transmission of the electrical signal Motor (33) developing torque is provided on the output shaft (7) and that the drive control device (76, 100, 108) to the electromagnetic Clutch device (63) a clutch drive signal (Ic) taking into account the output signal (S-, S2) from the determining device (77) can apply for the control torque. 8. System according to claim 7, characterized in that a reduction mechanism (50) for the transmission of the developed on the electric motor (33) Torque to the electromagnetic clutch device (63) is provided, its speed is decreased.